-LRB- CNN -RRB- -- John Travolta and Kelly Preston have returned to Ocala , Florida , with the remains of their teenage son , a family friend told CNN on Tuesday .

Actors John Travolta and Kelly Preston say they are `` heartbroken '' over their son 's death .

They left the Bahamas late Monday night , said Obie Wilchcombe , a member of the Bahamian parliament .

An autopsy was conducted Monday in the Bahamas on the body of the couple 's son , Jett Travolta .

The 16-year-old was found unconscious Friday while on vacation with his family in the Bahamas ' West End .

He was taken to a hospital , where he was pronounced dead on arrival , local police said .

The autopsy results have not been released , but employees of the funeral home that handled the remains said `` seizure '' was listed as the cause of death on the death certificate , celebrity Web site TMZ reported . Watch the latest reports on Jett Travolta ''

An employee who answered the telephone at the funeral home confirmed the report .

The funeral home said `` The body was in great condition and shows no sign of head trauma , '' TMZ reported .

TMZ is partly owned by AOL , part of CNN 's parent company , Time Warner .

The family 's doctor observed the autopsy , Wilchcombe told CNN 's `` Larry King Live '' on Monday .

The body was cremated , Wilchcombe said Monday .

He said Tuesday that a memorial service was planned for Thursday . Funeral plans have not been announced .

In a statement posted on the actor 's Web site , Travolta and Preston described Jett as `` the most wonderful son that two parents could ever ask for -LSB- who -RSB- lit up the lives of everyone he encountered . ''

`` We are heartbroken that our time with him was so brief , '' they said .

The couple also has a daughter , Ella , 8 .

Jett Travolta had a developmental disability that his parents have linked to Kawasaki disease , an inflammatory disorder of the artery walls that most commonly occurs in young children , and that can lead to heart disease .

According to the American Heart Association , `` About 80 percent of the people with Kawasaki disease are under age 5 . Children over age 8 are rarely affected . ''

`` They 're just a fantastic couple , very family oriented like a lot of people in our community , '' Ocala Mayor Randy Ewers , told Larry King . `` We 're very sad about the unfortunate events for one of our community members ... they 're part of the community . ''

Neighbor Jacob Urbowicz described the actor as `` just one of us . ''

`` He may be famous , but he 's just one of us here in the neighborhood . You know , we see the kids , and they see our kids . We 're all one family here , you know . It 's just not something that 's supposed to happen , '' Urbowicz told CNN affiliate WESH-TV .

Urbowicz said he remembers Jett Travolta as a happy teenager , the television station reported .

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Seizure listed as cause of death on death certificate , TMZ.com reports

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Jett Travolta 's autopsy was performed Monday in the Bahamas

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His body has been cremated , memorial scheduled for Thursday , family friend says

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Teen 's parents say he had developmental disability linked to inflammatory disease